1. Field of the Invention
The present invention relates to increasing the performance of docked portable computers to comparable levels with desktop computers.
2. Description of the Related Art
Design choices of a portable computer have become particularly challenging. In the past, portable or laptop computers have for reasons of weight and power consumption limitations typically performed at levels somewhat lower than desktop computers. It would, of course, be desirable for a portable computer to provide functionality, connectivity, and performance substantially similar or comparable to that of a desktop unit. Comparability or equivalency of a portable computer and a desktop unit in functionality, connectivity, and performance is termed desktop parametric equivalency (DPE). Docking stations which are also termed convenience bases have enabled desktop equivalence for laptop computers in functionality and connectivity. A docking station is a non-portable unit that typically operates from AC power and resides on a user's desktop. These bases allow for various port and adaptor connections such as keyboard, parallel, serial, and VGA (video graphics adaptor) connections. In terms of functionality, docking stations offer expansion via standardized I/O (input/output) buses, network controllers, and additional peripheral devices.
While docking stations have resolved the issue of equivalency in functionality and connectivity, docking stations have not been able to provide comparability of portable computer performance with desktop models. The performance of the docked laptop set has, so far as is known, been a generation behind the desktop set due to the different thermal and power requirements of a laptop set. For a portable computer, thermal dissipation and power supply capacity have been budgeted around the available processor performance for portable computers, so that a processor can work at its maximum capacity while operating on a stand-alone basis.
Improved processor performance as a function of processor speed is typically achieved, through higher processor frequencies. These frequencies may be provided internally or externally to the processor. As the semiconductor technology used predominantly in computers is CMOS (Complementary Metal Oxide Substrate) logic, the processor frequencies are associated with the power consumption of the CMOS logic. Achieving these higher frequencies for a portable computer has thus required higher core voltages used by the CMOS logic. The size of a portable computer power supply is proportional to its required voltage output. Higher core voltages for increased performance thus require a substantial increase in power supply size. An increase in power supply size compromised a mobile users need for small size and low weight from a portable computer. Therefore, the size of the portable computer has been a constraint upon improvements in processor speed.
Thermal requirements have also prevented improved processor performance for portable computers. Power usage in a portable computer is proportional to the square of the core voltages used by the CMOS logic, and also directly proportional to the frequency of the CMOS current. The higher voltages and frequencies necessary for improved processor performance caused significant amounts of additional heat within the portable computer. High temperatures in a portable computer affected the reliability of processor components, and also created undesirable heat concentrations or hot spots on the portable unit. An increase in processor performance thus would have typically required additional space in the computer for active or passive cooling of the processor. The increase in computer system size to accommodate this additional space would increase the size and weight of the portable computer, a factor contrary to the needs of laptop computer users.
Docking stations, as far as is known, have not aided the portable computer in overcoming weight and size requirements imposed by thermal dissipation and power supply capacity. These weight and size requirements have thus imposed a performance disparity between the docked portable computer and a desktop set. Desktop performance equivalency would, of course, be desirable for a docked portable computer, but so far as is known the power and size increases necessary for performance comparability have been significant deterrents.